Conceptual modelling of adaptive web services based on high-level petri nets
Date
2009
Authors
Zafar, Bassam
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Publisher
De Montfort University
Peer reviewed
Abstract
Service technology geared by its SOA architecture and enabling Web services is
rapidly gaining in maturity and acceptance. Consequently, most worldwide
(private and corporate) cross-organizations are embracing this paradigm by
publishing, requesting and composing their businesses and applications in the
form of (web-)services. Nevertheless, to face harsh competitiveness such service oriented
cross-organizational applications are increasingly pressed to be highly
composite, adaptive, knowledge-intensive and very reliable. In contrast to that,
Web service standards such as WSDL, WSBPEL, WS-CDL and many others
offer just static, manual, purely process-centric and ad-hoc techniques to deploy
such services.
The main objective of this thesis consists therefore in leveraging the development
of service-driven applications towards more reliability, dynamically
and adaptable knowledge-intensiveness. This thesis puts forward an innovative
framework based on distributed high-level Petri nets and event-driven business
rules. More precisely, we developed a new variant of high-level Petri Nets formalism
called Service-based Petri nets (CSrv-Nets), that exhibits the following
potential characteristics. Firstly, the framework is supported by a stepwise
methodology that starts with diagrammatical UML-class diagrams and business
rules and leads to dynamically adaptive services specifications. Secondly, the
framework soundly integrates behavioural event-driven business rules and stateful
services both at the type and instance level and with an inherent distribution.
Thirdly, the framework intrinsically permits validation through guided graphical
animation. Fourthly, the framework explicitly separates between orchestrations
for modelling rule-intensive single services and choreography for cooperating
several services through their governing interactive business rules. Fifthly, the
framework is based on a two-level conceptualization: (1) the modelling of any
rule-centric service with CSrv-Nets; (2) the smooth upgrading of this service
modelling with an adaptability-level that allows for dynamically shifting up and
down any rule-centric behavior of the running business activities.